Flight into known icing conditions

[cookmg]

As a newly minted instrument pilot, I would like to know how more experienced pilots deal with the threat of ice at cruise. If you are flying a basic SE (172, cherokee, etc.) do you never depart if you anticipate possible light ice? How important is it to have backup plans?

Consider, if the MEA for your route is 4000, the ATC preferred altitude is 6000, the temp is -1C at 6000, the temp is 12C at terrain/airport elevation across route, there are NO airmets or sigmets for icing, there is 1 pirep for light rime at 6000 along route. You could take 6000 and if you pickup ice ask for 4000. If you don't get it you might have to ask for priority or even declare an emergency. Since this could have been avoided given the indications of ice, is this negligent operation of an aircraft?

Basically, I'm looking for some general thoughts on operations near ice . . even light ice. How does the picture change when the flying is for hire? If you are flying light SE/twin NO deice boots under part 135, do your cancellation standards change?

Thanks.

Mike

 

[mike1mc]

We fly a Baron 58 with boots and all the deice equip under 135. The plane typically doesn't fly much during the winter for the reasons you listed. If we have a trip scheduled and the forescast shows possible icing along the route we immediately notify the customer to make other arrangements or upgrade the aircraft just in case. The ultimate decision is that of the PIC. The severity of the forecasted icing, PIREPS, and actual temps aloft all play in the decision-making process. Just make sure while doing your flight planning that you always have an out. Whether it be warmer temps below your cruise altitude, or alternate airports along your routing. Good luck!

 

[Airpiraterob]

could try this post on the cargo section. you would get alot of feedback. those guys plow through it all the time. First thing is if its expected along the route, make sure your plane is certified for known ice operation. and even if it is, try planning a route around the area its expected or even try to go on top above it all. Boots, hot window, all appropriate heated bits and pieces. Either way, always be careful-and most important- leave an out for yourself. Unknown and unforcast freezing rain can ruin your day...i lost 50 knots once. i dont ever want to do that again. (*shake*)

 

[mckpickle]

Basically under part 91 there is no restriction to legally fly into icing. HOWEVER, the FAR that covers this is the one about operating the A/C against the POH, which for a 172 should state no flight into know icing or something like that. Basically your only going to get in trouble with the FAA after you crash, so I guess just make a big hole!

But really be careful with a 172 in ice. Flying in the northeast I've had ice on every plane I flew. (that or I didnt eat for 2 weeks). The 172 was the poorest performer. Pipers were generally the best. Just always have an out. And try to make sure gravity is on your side. Climbing out of ice in a GA plane is scary and unless its light (the ice) you might not make it. Listen to pireps, and use controlers to ask the commuter guys. Not jet guys but old fasion prop drivers. Also ask for the OAT, and if the number sounds odd, ask again, the over worked underpaid guy in the right seat of the 1900 may have read off the TAT instead of the SAT. Good luck.

 

[flipflyr]

Another thing to add to this discussion. Find out base and tops reports along your route of flight. That should keep you out of the ice while in cruise... That is if you decide to go into know icing conditions.

 

[Deftone45075]

I think the most important part of your post:

How important is it to have backup plans?

This was answered. It's very important. One option is the base and tops reports. If you know it will be a thin layer and you can remail out of most of it throughout cruise, you might want to look into completing the trip as long as you have the following options. Warmer temps below you or above you that you arecapable of operating at based on MEA's and the performace of your airplane. Also, it's avery good idea to have suitable airports aong your route that you can get to quickly.

As for flying with a little ice on a 172, Bad idea. That airplane, as someone else stated, is pretty poor in handling ice, and the only acceptable accumulation is no accumulation. Once it starts building, you need warmer air or an airport very very close.

 

[metrodriver]

A back up plan is very important, just like keeping yourself a way out. It also depends on temperature and what kind of moisture you're dealing with, if any. Also how deep the layer of moisture is. At one 135 comp I flew for they had a weird statement that said something like: it's not 'known icing' unless you see ice building up.
If you ever pick up ice, be very adament about where you want to go: ATC, I NEED to climb /decend/ turn to.... because of ice.

 

[80/20]

Don't mix light airplanes and icing
Agree 100% with the above.
A pilot's respect for icing conditions will increase proportionally with practical icing experience. Many inexperienced pilots just don't understand how dangerous it can be. A C-172 is not the right aircraft for icing condition. Cancel and stay away from any potential icing because you don't know how bad it is going to be. Sometimes you might just pick up a little bit. But if you do it enough times you will eventually experience one or more of the following: Too much ice on your wings, iced up windshield, propeller vibrating so much that you have to throttle back, a stuck throttle or an engine with full or partial loss of power. Icing has been a contributing factor in many accidents, it can be challenging even for transport category aircraft certified for known icing.

 

[80/20]

An example of how bad icing can be even in aircarft certified for known icing:

An occurrence report from a Captain with 17 years in Boeing 737's.

B-737: " during climb from 4000 ft to FL 240, encountered unforcasted sever icing… 70-80% of windshield covered with thick ice within 3-4 minutes……..accumulation too rapid for window heat, sever engine vibration on both engines (Boeing recommends engine shut down when vibration monitors shows more than 4 …..but could not shut down both engines)……"

The engine manufacturer (CFM) studied the recorded data from FDR and ACARS monitoring system and changed their recommend procedures for icing condition.

 

[cookmg]

Thanks everyone. Glad to know that a conservative approach to ice is the way to go!

Mike

 

[Singlecoil]

...there are NO airmets or sigmets for icing, there is 1 pirep for light rime at 6000 along route.

I'm gonna get flamed for this, but I can't resist. Unless you are getting moderate or better icing, don't PIREP it. Obviously if it is below freezing and you are in the clouds, you are going to be getting some form of ice, at least a trace. When someone reports that, it becomes known icing, and makes the job much tougher for the general aviation driver to legally launch.

If ATC asks you if there is any ice, and you look out and see only a trace or very light rime, then the answer should be, "negative".

 

[Airpiraterob]

you're right...

sorry man...but i gotta.

if a general aviation plane is gonna launch into known icing.....

ill stop right there, the pilot of that plane is crazy if it's not a 'certified for known icing' airplane. I think reporting any icing. even trace icing helps save accidents from happening. trace icing can often be the opening band for the heavy metal ice that comes later. Someone jumps into a cherokee and blasts off (sorry...) into known icing. even if its trace, thats enough for a cherokee to well...not climb very well at all and slowly come down. and then find lower...but finding continued ice on the way down cause he/she is over a different part of land that migth be colder than the warm city they just left....or even freezing rain later on into it if they try to keep going.

been scared too much in a known icing plane to know that you dont mess around with ice. report it. all kinds of it when you find it. help the guy on the ground stay alive. it dosent make it harder for him/her to takeoff. it just makes it harder for him/her to fly into an icy cloud. something they shouldnt even think about to begin with.

flame off...sorry man this topic is just a big concern to me.

 

[cvsfly]

Re: Re: Flight into known icing conditions

I'm gonna get flamed for this, but I can't resist. Unless you are getting moderate or better icing, don't PIREP it. Obviously if it is below freezing and you are in the clouds, you are going to be getting some form of ice, at least a trace. When someone reports that, it becomes known icing, and makes the job much tougher for the general aviation driver to legally launch.

If ATC asks you if there is any ice, and you look out and see only a trace or very light rime, then the answer should be, "negative".

Well you knew the answer and you should get flamed. PIREPS are not the basis for determining "known icing". For one, not enough crews report PIREPS and when it is on icing days usually the only ones reporting are higher perf/equipped aircraft because small GA (low perf/not equipped) aren't flying. "Known icing" can be expected near the freezing level and visible moisture. There can be multiple freezing levels especially close to a frontal boundry and convection. Remember your weather briefing is based mostly on forecasts and the minute you get off the phone, most of it is old news, especially at C-172 speeds. Keep the PIREPS coming.

 

[mckpickle]

Just ask yourslef one question.

What will they say at the trial?

 

[WrightAvia]

An example of how bad icing can be even in aircarft certified for known icing:

An occurrence report from a Captain with 17 years in Boeing 737's.

B-737: " during climb from 4000 ft to FL 240, encountered unforcasted sever icing… 70-80% of windshield covered with thick ice within 3-4 minutes……..accumulation too rapid for window heat, sever engine vibration on both engines (Boeing recommends engine shut down when vibration monitors shows more than 4 …..but could not shut down both engines)……"

The engine manufacturer (CFM) studied the recorded data from FDR and ACARS monitoring system and changed their recommend procedures for icing condition.

.................................................................

Hahahahahaha....glad to see that the higher paid jet jock guys get to live in fear for their lives once in while too.

I spent my whole day at 6 and 7 thousand feet at plus 4 C and in light to moderate rainshowers. No ICE all day long except below 5,000 feet where the temp dropped to -4 C. Then some clear or mixed could be found.

 

[tarp]

Cookmg:

I'd like to take a stab at the cycle of life in a "seasoned" IFR pilot.

We start out in a "never get iced" mode. Clouds / precipitation / visible moisture plus freezing temps just are too scary as the posts above suggest.

Then one day we're coming home. Some unexpected but pretty light clouds come along (or maybe a little rain) and we get this very fine bead of ice on the front of the wing and the temp probe. While this is happening in flight, our blood pressure goes up, we stop talking and our wives/passengers ask whats wrong (because we are acting funny). We answer "nothing" and continue home. Landing safely we think "hey, I just picked up a little ice and nothing happened".

So on subsequent trips, we get a little bolder about the clouds and rain. Go up one day, barrel through clouds and "known icing" areas and nothing. Not a lick of ice on the airframe. Maybe this icing stuff is overblown.

Then, one day we get stung. The clouds are a little thicker or we are get forced to go up. You're at 10,000ft in a small GA airplane with no equipment and suddenly there's 6,000ft of clouds below you and only freezing temps. Now you stop talking (even to yourself) because your mouth feels like the sand outside of the Las Vegas desert. It's -18C outside and you are sweating.

Forced to descend through the clouds you try to formulate a plan that will cause the least damage. You want to land with fuel in the tanks, an airport with above freezing temps would sure help, a place where the clouds are thinner and the winds at your back - those would be good things. You start a descent as the ice sticks to the plane like an old fashioned refrigerator freezer in bad need of defrosting. First, that little bead that you allowed before, then the front of the wing turns all white, yes it's building now on the front (oh geez, when did I sign up to be a test pilot) and then the prop starts getting a little vibration and then bigger and bigger as you realize that everything except the heated pitot tube is iced to the max.

Since you are going to live and complete the cycle of life, you break out of the bottoms of the clouds with an iced up plane, trying to look sideways out your windshield and doing everything possible to get that cheap little defroster to melt you a hole so you can see straight in front. You level the plane out and realize that the nose wanted to fall over a little too quick - was it trying to stall? Better keep the speed up - who knows what the stall speed is on this new wing design just created with 2 inches of rime on the front. You nurse the bird down to a landing that just flops on the runway - it just stalled onto the pavement without a beep from the stall horn.

You taxi to the FBO, get out and see this incredible sight of what was once a friendly little aircraft, you walk around and see that the stall horn is completely blocked with ice (you hadn't thought of that one!) - the heated pitot tube (thankfully) kept your airspeed alive or your goose would have been cooked.

And then you knowingly answer webboard posts having lived through the cycle of life. You profess that clouds, visible moisture, precipitation and below freezing temps are a recipe for disaster in unequipped airplanes - and they are! So when you push your luck and see that first little bead of ice - GET OUT! You'll be glad you did.

Good judgement comes from experience. Experience comes from making bad judgements in the past. You can learn from all your mistakes except for the one that kills you.

 

[Deftone45075]

Fortunately, you can also learn from the mistakes of others.

Thus:
Acceptable amount of ice for light GA airplane = NONE

That "way out" everyone keeps talking about is crucial if you are planning a flight were there is a CHANCE of icing. If it's KNOWN icing, don't go. Live to fly another day.